Adventures in Worldbuilding: A Question About Naming

Random question for you writerly types:

I’m currently working on a fantasy world, as I said a few days ago. The world is coming together well enough. Figured out the relationship between geography and climate (though not orbit and climate, sadly, which I cannot seem to find useful information for easily calculating). My problem now stems from a problem of naming, which seems to be a trap between oddly French sounding upper royalty “houses” and oddly middle English sounding stuff for most of the lower “houses.”

So I suppose the question is this:

Should I change the upper houses to reflect the linguistic heritage of the lower houses, or could there be a valid reason from a linguistic perspective for those names to stay with their French influence (accidental) if there are no French-like cultures surrounding them (and, thus, no invasions, cultural transference, and so on)? 

I’m leaning towards changing the names, even though I like them as they are (the upper houses are Echeler, Millard, and Dorian, with Lyemark as the only slightly Frankish/Middle English outlier).

(The lesser houses, unfinished though they may be, are currently named as follows:  Leyne, Pyne, Trym, Cambryn, Caethyn, Prymsteyn, and Aestyn — yes, I am fairly obsessed with the Y right now.)