When looking at the page showing my closure votes, I noticed one of the entries shown (deleted).
What does that mean? As far as I can see, the question has never been deleted.
At some point in that question's history, the question gathered enough close votes to be closed.
At some point after that, the question gathered enough reopen votes to be reopened.
When the question was reopened, all of the close-votes on the question are deleted, meaning the question needs a whole new five close votes to be closed again - the close votes from before the reopening do not count towards the new close vote count.