Not sure I fully understand the problem but I'm guessing the bit that is "moving" the row you are working on is:
Range("L4").Cells(i,j) as i will increase through your row counter and keep moving to a new row. I'd guess what you need is more like:
For i = 1 to dim1
for j = 1 to dim2
cells(4,12+j) = arvar(i,j)
next j
next i