Mr Worf: "an hot ...". Strictly correct but try saying it out loud - its quite painful! I too was taught to use "a" as the indefinite pronoun when the noun had h as the initial capital letter. "An" would normally be the correct form if the noun's initial letter is a vowel (a vowel, not an vowel).

Any en_GB speaker will probably do one of two things here:

  "an 'ot" - where the h is dropped and "an" and "'ot" sound like a bit like "annot"
  "a hot" - here the a becomes ay (rhymes with hay)

I'm very impressed that the old school rules still turn up. I do own a copy of "Usage and abusage" somewhere but it is and should be largely consigned to history.

When you trot out a phrase like:

"Well what's the difference between a lamprey and an hot dog?"

I can't help but notice a lack of a comma post "well"!

A lamprey is a fish and a hot dog is a sausage. The first is a living organism and the other is a processed food.

Cheers mate