I have an antique book with the genealogy of the main families in the Richelieu regio, of which the Loiselle. In this book I have the genealogy of your branch of Loiselles. The marriage listing in this book (published in 1927) tells us the following:
The marriage of Jean Baptiste Loiselle to Monique Casgrain took place in Sainte Marie in 1844 and was his second marriage. His first marriage was to CÚleste Nadeau in 1841. The listing maybe incomplete as it does not reflect descendance. He indeed was the son of Pierre Loiselle and and Marie Demers, who married in Saint Marie also in 1814. The listing shows Pierre was one of 6 married children of Jean Baptiste Loiselle and Isabelle Dutilly. Jean Baptiste and Isabelle married in 1785. Jean Baptiste was the first of 7 married children of Jean Baptiste Loiselle and Apppoline Desbled who were married in Pointe aux Trembles (Montreal East) in 1748. And this Jean Baptiste was one of 2 married children of Joseph Loiselle and Marguerite Beaudry, married in Pointe aux Trembles in 1710. So, if you are a descendant of this couple, that means you and I are distantly related, as this couple are also my own ancestors. Their son Toussaint, brother of Jean Baptiste who married Appoline, is the ancestor of my branch of the family. Joseph Loiselle,married to Marguerite is son of Joseph Loiselle married to Jeanne Langlois, and who is son of the first Loiselle who settled in Montreal and, who as you may know was a locksmith and married Marguerite Charlot in 1648.