All I can say is that I have on occasion had lucid dreams immediately after crossing the sleep threshold that continued what was on my mind at the time. I was, in fact, not even convinced I was sleeping. This would usually change when I realize that something happened that I didn't make up, an unexpected turn of events. Like walking around a corner and seeing a window with outer space and Saturn outside. It can happen that one gets so excited at the thought that one wakes up then.

The technique sounds worth trying.