A home owner from Toronto, Canada says:
May 17, 2016
Hi, The handle broke off the lock and there is no way to open the window or remove the lock, unless I saw off the lock inside. Attached is a photo. I don't know what brand it is.
Tom from SWISCO responded:
May 18, 2016
This is always tricky to deal with. Try using a screwdriver to manually throw the lock so that you can remove it. Otherwise, the only other option would be to cut it out. If that happens to be the case, you may need a local handy person to help you out.