Ahhh, I beg to differ, sir. I believe the “an” is sometimes used in front of a word beginning with “h,” as they are sometimes non-affricitave, if you will, or soft.
As in “An honorable man would not hold it against me for correcting his grammar.”
This a common misunderstanding of the rule. It’s not the letter but its sound that dictates which indefinite article should be used. The rule is that you use ‘a’ before words that start with a consonant sound and ‘an’ before words that start with a vowel sound. If you simply judge from the letter and not its sound it would be normal for you to say “She is an one-issue voter” or “Rick is a NBA fan.” Similar rules apply for the word ‘the’ (pronounced thee) and ‘the’ (pronounced thuh).