If the main clause is long enough it is possible to put the temporal clause after the verb and before the “other stuff” at the end of a sentence. This is common in German even though it is not possible in English:
Die Freunde machen, seitdem sie die Uni abgeschlossen haben, einmal pro Jahr einen Wanderurlaub.
The friends go on, since they graduated from university, a hiking trip once a year.
You can learn more about placing time phrases within German sentences from our post on German time adverbials!