Is it Harmandir or Har Mandir?  

I don't understand why sometimes it's one word? I mean if one guru's name is Har Rai. Or Har Krishn. In Hinduism they might say Har Ram. Or Har Krishn. Or Hari OM.....So....Why is the Temple not Har Mandir? Why is it one word like like then Harmandir? I mean im not trying to fight. Im asking. Ive tried figuring this out before to. 71.105.87.54