i saw the name Ascelin and thought it looked like Asselink (a Dutch surname). Asselink has the same origin as Esselink, which is like Hesselink, which is like Hessels and Hessels means 'son of Hessel'.
i'm sorry but this isnt all:
Hessel is a Dutch male name, with variants like
Hasse and Hesling (notable!, looks like
Aisling). It's meaning is unclear, but there are six possibilities given:
1) from the Germanic
hasan which means 'beautiful' or 'smooth'
2) it's taken from the Hessian people, living in Germany
3) nickname of names beginning with
hart- like
Hartmann4) nickname of names beginning with
hade like
Hedwig5) nickname of names beginning with
her- like
Herman6) nickname of
Hendrik (Hezelo is a nn of
Heinrich)
...time to rest now...
let's go on:
personally i think the derivation from the germanic
adal is not true. this above makes more sense, because it all knits the web together (Hesling and
Aisling;
Ashlyn being derived from
Aisling, as BtN says; Ascelin, Asselink and
Ashlyn all like each other)
It seems pretty clear that Asselink and
Ashlyn are from the same origin. so i think it's safe to say that the same is applied for Ascelin.