Help with sentence word choice

All four versions are grammatically correct.

I'd say

'Should/shall I wear an orange dress or a red one?'

Thank. How about:

Should I wear 'a' orange or a red dress?

Specifically, the use of 'a' instead of 'an', would that also be correct?

No! That is completely wrong.

Why is that? Do different colors go with different words. For example:

I fell that 'an' does not work with black dress.
Should I wear an black dress. Sounds odd. I think it should be should I wear a black dress. But when using the color orange, the word 'an' sounds good! Please explain? Does it just depend on the color?

Colours have nothing to do with it.

If the next word begins with a vowel sound, use 'an'. If it begins with a consonant, use 'a'.

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Thank you. That was helpful.

So is what I explained above regarding the black correct?

Would these be correct:
Should I wear a black dress or a red one?
Should I wear a black dress or an orange one?
Should I wear a black or orange dress?

Can I have to a's just as in the first one?
And can the 'an' be excluded before the orange, just as in the last example

They are all correct.