Eurogamer is reporting that TES V will follow on directly from Oblivion. Their story comes from a journalist who sat behind "a person involved in the game" on a plane trip, so should be taken with a large pinch of salt, but is still interesting as so far in the Elder Scrolls series, no game has been a direct sequel to another.
http://www.eurogamer.net/articles/2010-11-23-rumour-elder-scrolls-5-in-the-works