I followed Richard Mabeys recipe from "The Full English Cassoulet" for Corsican Curd cheese, it recommended Lemon juice as the curdler, but I found this to only curdle a little, so I used white wine vinegar, using enough until I'd separated the curd from the whey, I have also tried cider vinegar too but I thought the overall taste was better with the white wine vinegar, I washed the cheese gently afterwards whilst it drained to wash off any strong taste.
Hope it works well for you too.