Hi Lionel
Blitz is actually a German word and means "lightning, flash, thunderbolt" etc. The term "Blitzkrieg" has been also used for the early German WW2 attacks on France, Holland etc.
Until I went for the first time to Australia, for me a Blitz truck was always a German
Opel Blitz. They were the backbone of the WW2 German Army. Opel belongs to GM since 1929. That's probably why the term "Blitz" swapped over the pound.
Greetings
Chris