That's not how Quora works. They allow direct question navigation (copying the URL of a question and accessing it directly from the browser navigation bar). But if you access a question page and the immediately browsed page was from Quora as well, then you are asked to login. That's a bit different from what you ask.
1. Would that work for you?
Also there is no "login prompt" in Q2A (unless you have coded that your self, of course).
2. Would it work for the user to be redirected to the login section and once they login they're automatically redirected to the question they were browsing?