I think there's another technical solution.

Instead of having a link directly to the article, have the link go to the discussion page instead, but with an added header.

That extra header would check for a cookie. If that cookie is set, no action. If the cookie is not set, set the cookie, then forwards the user to the actual article.

Then, when you finish reading and decide it's worth an up vote, when you go 'back', you're already at the discuss page where you can vote the story itself up, as well as comment on it.