Frank is a honorable man.

The intricacy I want to point out is when to use "a" versus when to use "an." There is a common misunderstanding that you use "an" before words that start with a vowel. The converse is that you use "a" before words that start with a consonant. Here's an example using that thinking:

Frank is a honorable man.

Here's another:

At the funeral on Saturday, Tim gave an eulogy.

Using "a" in front of words that sound like they start with a vowel requires back to back glottal stops. This is difficult. It doesn't roll off the tongue.

Likewise, pronouncing "an" takes more work than does "a" (the tongue must come into play), so if the noun following the article doesn't start with a glottal stop, it's easier to use "a."

I suspect the usage was formed based on ease of use. Here is the rule: use the article "an" in front of words that sound like they start with a vowel and use "a" in front of words that sound like they start with a consonant.

Now you know the true rule regarding when to use "a" and when to use "an" and we can say with certainty that Frank is, indeed, a very honorable man.