Since

[Perikles]

I didn't know that Since means Puesto que.
Only I knew that since means desde.

I hope that you can clear mi doubt.I'm afraid since has two completely different meanings, as pjt says. One is desde que and the other is puesto que.

Since coming to London ...
Desde que vino / vine / .. a Londres ...

Since that is not the case ...
Puesto que no es ése el caso ...

[irmamar]

Thanks everybody. :)