Nice one, TR!
Tony, I myself would have used the hyphenated version without even thinking about it, thus being just as "wrong" - so to speak - as you.
Americans are getting rid of hyphens almost completely, it seems, producing absurdities such as 'coworker' to mean a colleague...ie a co-worker. Any time I see their version, I invariably read it as 'cow-orker' which gives rise to all sorts of dark imaginings as to the meaning of the verb 'ork'. At the present rate of import of americanisms, 'lightbulb' will soon be perfectly OK, so hang on in there! Cheers