Ruth,

Try this version:

Range("J" & (row - 1)).Formula = "=L" & (row - 1) & "& Char(10) &" & "L" & (row)
This is the same, with some simplification of the string manipulation:

Range("J" & (row - 1)).Formula = "=L" & (row - 1) & "& Char(10) & L" & (row)
Both concatenate two cells with a return character to get them to wrap within the cell - not sure if that is what you want.