Hei May-Linn,
Loki is the original Old Norse and Icelandic form which is used in many other languages as well (e.g. English and
German).
Loke is a modern Scandinavian variant in Norway, Sweden and Denmark.
The same happened to the name of some other Gods (Oðinn bekame
Odin in many languages while in Sweden the form Oden is used).
Regards,
Satu