There's a similar way described here: http://www.gimpusers.de/tutorials/blitze
(although it's a German one)
Anyway, yours is clean and quick, the audio is clear, everything fine there.
The only small thing I dislike about your tutorial (and the same thing applies to pretty much 90% of all Gimp tutorials) is that you say "select a value of XY" (in the difference clouds menu, Gaussian blur menu). The values change from image to image, especially when someone wants bigger lightning strikes etc. Giving exact values stops the creativity in my opinion. But most tutorials out there do it that way, so I might be alone with my opinion there
Just a quick side note: Gauß/Gauss (the mathematician after whom the Gaussian blur is named) is natively pronounced like GOUSS, it rhymes with HOUSE in English. I remember GimpKnowHow mentioning that in some of his tutorials, too