Originally Elizabeth/Isabel (apparently the names are the same in Medieval English/Latin) was married to Walter de St. Valery, d. 1061, and then she married Joscelin Courtenay. However Walter apparently lived until after 1086, and possibly after 1097; so I don't know if they got a divorce, or if two sisters married the two gentlemen - and Isabel and Elizabeth are not the same person. There are sources for both marriages.