You answered your own question in a previous post, but went too far by including 'no skill at all'. No skill, no art.
However, I agree with your revised statement:
I don't care how much, as long as we agree that they are inseparable.
Well... no skill at all is an amount of skill. (that's really lame, isn't it?

Sorry!)
Anyway. Everything we do requires skill. So everything we do and skill are inseparable.
But that's not the point.
Skill is not the differentia specifica.
If art requires no more skill in particular than, say, writing a letter, it would be hard to say that skill is a defining attribute of art, without also having to conclude that writing a letter is art.
And creating art does indeed not require more skill in particular.
The amount of skill needed depends on what the artist wants to make what medium do what exactly. And that amount may be even less than required for tieing your shoe laces. And conversely, things we would not call art may require tremendous amounts of skill.
But that's all about amount.
Perhaps there is a specific skill that, no matter in what amount, is required to create art. Maybe the difference is not in the amount, but in the sort of skill.
But is it? Is there a specific skill that could be the thing that makes or breaks (by absence) art?
And is that then still anywhere near what you meant?