I have been doing Rocheleau genealogy and have gone back into my family as far as 1680. Have not found an Alexander. I do have the Rushlow spelling in the family. Many found this spelling easier. Look under (Rocheleau) and also many families of French decent named the boys Joseph.It was placed as first name example(Joseph Alexander). Many Rocheleau's (Rushlow) in Ste.Anne des Trois-Rivieres, Quebec,St. Cuthbert, Berthier Co, Quebec.Good luck.