I do not speak French, but on Altavista translations, Deslaurier comes out as Bay-tree. Perhaps someone fluent in French could be more helpful. As far as name changes, any genealogist can tell you that names are made to be changed. Sometimes they translate them (Anglicize)into English. My grandmother's surname was Belleheumer but her parents were later listed as Goodnature. Also census takers and other public officials often spelled names like they sounded, hence changing the spelling. Good luck in your search.
Phil Bousley (Beausoleil, Beausoleau, Bouslay, Boslay, Boseley, Bosly, and in the French manner dit. Malboeuf)