User blog comment:Bobdave/Epic Rap Battles: Modern vs Classic. Tupac vs Bach/@comment-3401602-20170112050236/@comment-28960899-20170113021452

You're allowed to put "an" before a word beginning with "h" if the emphasis is not on the first syllable.

For example, "an hisTORian" is allowed, but "an HIStory" is not.