Don’t know where else to post this, so here goes. We have a minor controversy over the use of “a” or “an” before an aspirated “h”, such as in “historic”. Here’s what others have to say:
When ‘an’ precedes a noun starting with the letter ‘H’, even when the ‘H’ is not silent, there may be a tendency when speaking to make the ‘H’ weakly aspirated, as for example in “an hotel”. However this is not a rule, and we could equally well say “a hotel” with a strongly aspirated ‘H’.
In some dialects of English, such as London cockney, the ‘H’ is regularly made silent in speech, and the indefinite article ‘an’ is used, as for example “I know an 'otel where you can stay”.
And from the following source, which seems really good -
DECIDING USAGE (2000) by . Stephen Sherwin Professor of English (Emeritus), State University of New York
Whether a or an is used depends upon the pronunciation, not the spelling, of the word it modifies.
The indefinite article a precedes words beginning with a consonant sound: a button, a yam, a unique device, a European, a eulogy, a zone, a Xerox. The article an precedes words beginning with a vowel sound: an audit, an ax, an eye, an egret, an icicle, an igloo, an umpire.
Words beginning with h cause the most uncertainty [!!]. A is usual when h is pronounced (stressed or unstressed): a hostel, a hotel, a history [hmm], a hyphen, a hurdle; a hysterical, a hypothetical, a habitual.
When h is not pronounced (as in honest, heir, hour, herb), an is standard.
I would hazard a guess that these usages apply to written “h”'s also.