Dollard Family Genealogy Forum
I've never heard of Delard being used as a spelling variation of Dollard, but Peter Dollard, born about 1790 in Ireland immigrated to Nova Scotia and married Sophie Petipas. They had a number of children who married into French families in Nova Scotia, Prince Edward Island and New Brunswick and descendants spelled their surname in a number of different ways. It's my understanding that the differences in spelling were due to the translating, pronunciation, spelling of an Irish surname to French. So your Marie Delard could be a descendant in this line or another line with yet another spelling variation, but I've seen nothing that would establish that as fact.
Dollard Family Page http://members.gtw.net/~dollard