I recall dealing with a situation like that, and what I wound up doing was to just go ahead and split on the desired character.   Then, I simply examined the preceding element in the list, to see if it ended with an escape-character.   If so, I combined the two elements and moved on.

I am sure that there is “regex mojo” that would have done it.   (There’s a Golf section in this site for more reasons than just amusement ...)   But what I did was clear-enuf, and it worked.