I think some of you are missing the question here:

Any suggestions on how to regain ability to control my lucidity? [/b]
it's not attaining lucidity, it's maintaining it.

Awhislyle - I've experienced this same "blackout" that you describe. It usually happens right at the onset or breakdown of the dream.

The best thing to do is first, relax. If you get excited or frustrated you're likely to lose the lucidity. If you just wait a little bit and pay attention to any sounds you may be hearing - eventually a dreamscape will fade in. Some people say that they simply imagine opening a door with the belief that there will be an outdoor scene behind it or something. Second, once you are lucid and there is a dreamscape established, try to interact with your surroundings as much as possible. The trick is to keep your mind busy and distracted to the fact that it is (in reality) lying back in bed. The more stuff you do in the dream - the longer your lucidity will last. Once you start feeling like it's all slipping away, do some of the tricks on maintaining lucidity posted here on the site.

Here's two of the most popular techniques in prolonging lucidity :
1) Rubbing your hands together
2) Spinning yourself around (standing up with arms extended)