I am using this formula;

=VLOOKUP(A1,Sheet1!A:L,10,FALSE)

In worksheet that contains my array, the cells in column 10 either have a time in them (in 24hr format), or are completely blank. The formula is working fine as long as there is a time in the cell column 10. If the cell in column 10 is completely blank, the forumla returns 0:00 which is midnight. That's not what I want. If the cell in column 10 is blank, I want my formula result to be blank. How can I accomplish that?