Is Lachlan pronounced Lock-lan, Lock-len, Lock-lin, Lock-lun, or Lock-lon?

Is Lachlan pronounced Lock-lan, Lock-len, Lock-lin, Lock-lun, or Lock-lon and is the vowel, whichever way it is, a long or short vowel sound? Example of a word please. I have only read the name but have never heard it spoken. So I was just wondering how exactly it is pronounced? Thanks!