Usage of "Since Before" ?

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May 14th 2012 04:06 English Grammar
I'd like to know natural expressions used in the following situation.

Time
past <----- A ========== B ========== C -----> future

Time A: "You" came.
Time B: "I" came. You probably recognized me, but I didn't recognize you.
Time C: We saw each other and are talking now.

At the time point C, could I say, "Have you been here since before I came?"
And, is it possible to say it without a perfect tense, like "Are you here since before I came?"

I encountered such a situation some days ago and couldn't make a correct sentence then.
After that, I found the phrase "since before", so I want to know if it works.