Does the usage of an vs a depends on the pronunciation: a history, a hobby, but an hour, an honor.

Yes. If a word begins with a vowel sound, then the correct article is an; otherwise, if it begins with a consonantal sound, the correct article is a.

Because hour is typically pronounced with a silent h, an hour is correct.

I wrote a blog post about an vs a on the EL&U blog some time ago, and it covers a wide variety of other cases that you might be interested in.

Does the usage of an vs a depend on the pronunciation: a history, a hobby, but an hour, an honor.

Yes. If a word begins with a vowel sound, then the correct article is an; otherwise, if it begins with a consonantal sound, the correct article is a.

Because hour is typically pronounced with a silent h, an hour is correct.

I wrote a blog post about an vs a on the EL&U blog some time ago, and it covers a wide variety of other cases that you might be interested in.