The two Arnaud brothers were the sons of M. Bertrand Arnaud, prosecutor of the Parliament of Bordeaux and of Dame Marguerite du Munsay, of Saint-Michel, city of Bordeaux. The eldest, Bertrand, married, in Québec, Mademoiselle Louise de Xaintes, sister of Madame Charles de Monseignat. The second, Jean, married, on November 27, 1690, Marie Truteau, daughter of Etienne Truteau and Adrienne Barbier; he is the father of Sister Saint Arsène, who was therefore the great-niece of our revered Sister Barbier, in religion "of the Assumption". The latter was superior when, during the night of February 24 to 25, 1695, a fire broke out at the Hôtel-Dieu, and the Blessed Sacrament was taken to the home of her niece, the wife of the merchant Arnaud, where it remained until morning. Four years after this incident, such a happy one for her family, Marie-Marguerite Daniel came into the world on January 15, 1699. She entered the noviciate in 1717, as we see in a letter from Bishop de Saint-Vallier to Sister Charly of the Blessed Sacrament, dated October 31 of that year: "I give my consent and my blessing to Sisters Arnaud and de Quenneville." Since her aunt "of the Assumption" was still alive, she drew from a good source the virtues of our holy state, and applied herself especially to the practice of abnegation, that she must have had the opportunity to practice so many times in her difficult career.

In 1733, Sister Arnaud, 34 years old at the time, was named to accompany Sister Trottier in the reestablishment of Louisbourg; she worked there for twelve to thirteen years, that is to say until the capture of Ile Royale. Sister Saint Joseph had left for Montreal the previous year; so that Sister Saint Arsène found herself Superior of the poor exiles when they were driven towards the shores of Rochefort. After having them transported to the Hospital at La Rochelle, and after having received the last breath of Sister Saint Placide , she approached the French government in order to receive the allowance that was promised to them in Louisbourg because she did not want to be a burden to the Sisters of Saint Etienne Hospital who already had trouble subsisting. She repeated her request many times; because an ill-intentioned subaltern intercepted her letters and the aid sent to her. When Ile Royale was returned to the French in 1748, Sister Arnaud was disposed to go there with her companions; but before leaving, she wrote to M. de Maurepas describing how helpless she was to make any preparations for her voyage. Passage was granted to her and to her companions with 600 pounds for the preparations for the voyage and it was settled that in Louisbourg they would be given the regular allowance... consequently, they set sail in the month of August 1749. When they arrived at their post, Sister Arnaud wrote to Sister Saint Pélagie, Superior of the Community, to give an account of her administration and to point out to her that the poor health of her two companions prevented them from withstanding the difficulties of the position. For this reason, Sisters Saint Gertrude and Saint Louis des Anges were replaced by Sisters Saint Thecla and Saint Vincent de Paul. The same trials that had assailed the mission of Louisbourg before the siege swept back down on it; on the outside, the difficulties were innumerable; on the inside, hard work, painful sacrifices, continuous hardships... Finally, in 1758, a second siege, fears, alarms, exile and death of one of them, except that Sister Saint Placide died only after they had arrived in La Rochelle, while poor Sister Saint Thecla died on the ship and was thrown into the sea; and except too that the survivors went into exile for the rest of their lives, and were never to see Cape Breton or their dear Community again. "We are at the Saint Etienne Hospital, where I had stayed during the last war, wrote Sister Arnaud to Sister Saint Simon, Superior. These young women have received us with many signs of their great kindness; we are well off here, they spare nothing to ease our pain. But, my dear Mother, we know well that we are not in our milieu: I entrust myself to divine Providence which has never failed us."

During the six remaining years of Sister Saint Arsène's life, together with her companion Sister Saint Vincent de Paul, she occupied herself with teaching a few young persons who had been brought over from Louisbourg. When she had lost all hope of returning to Ile Royale, in 1760, she offered herself to the French Government to go to teach at Belle-Ile en mer, or elsewhere; she also thought about returning to Canada. "Madame Saint Arsène is still uncertain about her fate, M. Ranjart, a merchant from La Rochelle, wrote on March 20, 1764, to know whether she will return to you or if she will go to Miquelon; she would prefer the former."

"With regard to your dear sisters, wrote M. de l'Isle-Dieu the following April 21, I assure you that each day I am more and more edified by the way they conduct themselves and by all that I come away with. They are more occupied with your needs and with those of their dear house of profession than with their own, and they want to deprive themselves of their necessities to send them to you."

Shortly after receiving the aforementioned letter, Sister Saint Arsène died at the Saint Etienne Hospital on July 5 at the age of 65 and 47 years professed. Her service was sung in the church of Saint Bartholomew in La Rochelle and she was buried in the parish cemetery.

Here is the act of burial:
"Extract from the register of deaths
"Of Saint Bartholomew Parish
"In the city of La Rochelle.

"The year of grace, 1764, on July 6, was buried in the cemetery the body of Miss Marie-Marguerite Daniel Arnaud, daughter of the late Messire Arnaud, merchant, and of the late Lady Marie-Marguerite Truteau, native of Montreal, Canada, religious of the Congregation of the said Montreal, under the name Sister Saint Arsène, Superior of the mission of Louisbourg, died the previous day in the house of the Saint Etienne Hospital at 65 years of age having spent 47 years in religious life.

Witnesses: Miss Marguerite Bénard
Miss Ursule Malzard
Antoine Epinay, Priest of the Oratory
Pastor of Saint Bartholomew

On July 26, M. de l'Isle-Dieu wrote to the superior of our Community: "Please find enclosed, Madame, a letter that dear Mother Saint Vincent de Paul addressed to me for you, and by which she undoubtedly informs you of the loss of dear Mother Saint Arsène, that is a true and very great loss for your Institute."

In a letter from M. Rangeard, dated March 26, 1765, we read: "You will learn of your of loss of Madame Saint Arsène for which we are very sorry. Madame Saint Vincent de Paul still remains here; she is waiting for the decision for her."

To the Most Reverend Mother Saint Hélène, of the Hôtel-Dieu de Québec in Canada

I cannot express how grateful I am for the letter I had the honour of receiving from you at a time when I could not hope for this consolation. I cannot describe to you the details of the sorrow and the crosses I have had to bear for the last eight months. I cannot understand why our beloved Saviour does not put an end to my meagre existence... after all the fears and miseries that this cruel war has caused us to experience.

None of this, my dear Mother, was as difficult for me as the death of Sister Saint Thecla. Four days before the departure from Louisbourg, she fell sick with a very high fever; the English forced us to board the ship shortly despite all my supplications to wait a few days... We had to leave and she died ten days later on August 30. I had the sorrow of seeing her thrown into the sea after having suffered terribly in every way, crowded as we were on the ship, there was not even room to lie down, we lacked everything that could have brought her relief.

These reflections have caused me sorrow that I cannot overcome. I recommend this dear sister to your holy prayers and to those of your Community; I ask you, dear Mother, to inform Sister Saint Martha about this. I have enclosed a letter for her. Never has there been a siege as cruel as this one we have just had; I cannot think of it without being frightened and what increases our sorrow is to think of how much our dear Canada is in danger of such a fate; all that we hear in this regard distresses us, but, I hope that God will send help; the Blessed Virgin will not allow these unfortunate ones to destroy his temples.

We are at the Saint Etienne Hospital in La Rochelle where I had stayed during the previous war. These ladies have received us with many signs of friendship; we are comfortable here, they spare nothing to lesson our sorrows; but, very dear Mother, we are not in our milieu; we have lost everything that was at our mission in Louisbourg; the English had the advantage of finding this house well furnished, without our even being able to bring with us any linens or clothes. Although we have lost everything, I hope that divine Providence will not abandon us, I place all my trust in Her and in Him willingly making the sacrifice. I would be well compensated if the Lord were to receive the little that I offer him for the remission of my faults: all I am doing is leading a paltry life that is boring.

I thank you, very dear Mother, for all the kindness you have shown our poor mission and me in particular; I am as grateful for it as I can be and I ask you for the help of your holy prayers; allow me to ask the same favour of your dear Community and to give them my regards and those of Sister Saint Vincent; it is this grace that I ask of Him to grant you and her who is grateful and respectful,

My reverend Mother,

Your very humble and very obedient servant, Sister Saint Arsène of the Congregation de Notre-Dame. 
At St Etienne Hospital in La Rochelle, this February 12, 1759.