This calls for a Swedish pronunciation lesson! ;D
K before a soft vowel (e, i, y, ä, ö) is pronounced sh. But for some reason it's a rule that's often ignored in names, so it really only applies to
Kerstin (SHESH-tin, because rs = sh as well) and word names like Kämpe. Names like
Joakim,
Kevin,
Torkel,
Jannike and
Rakel are all said with a normal hard k. So unless you're going to learn the language, not just the names, I suppose you don't really need to know this. :P