"A" or "an" are troublesome in other ways. A recent battle arose in my bailiwick: an agreement was identified in a draft news release as being "AN historic document." When the draft was submitted to the public affairs professionals, it was purged of all "an" articles and substituted with "a."

The public affairs folks cited with great emphasis their source: the Associated Press Style Manual.

Grammarians around me are not happy with that; indeed, when the release was orally presented, and the speaker tried his best to evoke, "a historic," it cause disruption by the speaker who proceeded to edit on the fly with "an historic."

The H in "history" used to be silent, but now is not, and hence the confusion. No one would disagree that "an honest man" is correct, and not "a honest man." If the initial consonant has a vowel-sound, then its an "an". (An honorable man). So I guess it depends on whether you assign an article to "history" based on its pronunciation today, or its (h)istoric pedigree.

Some style manuals suggest using a before forms of histor- in which the stress is on the first syllable and an otherwise. Hence, an historic but a history. This is style, not grammar. You should teach those grammarians to suck eggs.

Grammarian sounds a bit like grandma, but doesn't make this phrase about grandma applicable to grammarians. ;-)

In speaking it also makes a difference in flow whether the a in front of the h is long or short. (besides an sounds more formal)