When can you omit the possessive on an honorific?

Question

I was considering honorifics and I realized that sometimes we include and sometimes we omit a possessive in front of them.

I was wondering if there was a formal rule for such?

For example:

Your highness, the French delegation has arrived.

vs.

Highness, the French delegation has arrived.

Obviously, the your has been omitted here (or perhaps elided).

But, there are other honorifics where this is never done. For example: when addressing the mayor or a judge (in AmE), you might say "Your Honor", but you'd never say, "Honor". Rather, you'd say Mr. Mayor or Judge in those cases.

Is there a rule to this, or is merely that your has been elided in the above example, and it should have been written with an apostrophe:

'Highness, the French delegation has arrived.

Note: I'm deliberately ignoring the honorifics that never carry a possessive: Mr., Mrs., Dr., etc.

Answer 1

This varies between countries in which such honorifics are used in a system of peerage.

In Britain you would always use Your Highness the first time you addressed someone, never Highness. Then if you addressed them again, you would use Sir or Ma'am.

In Europe the shortened form Highness is sometimes used. However, this is usually a translation of the form in the local language. If it not usual to use the possessive, then it gets omitted in the English representation.

For diplomatic or religious titles, Your Excellency or Your Eminence for example, the "Your" is also always used.