Are you sure you have hidden it an not just set it really narrow.
Highlight columns AH and AJ and goto Format > Column > Width and type a
number in the box. You can reset the widths of AH and AJ once you get
AI back.
try selecting both AH and AJ, set the cursor such that the shape is a set of
parallel lines with a line coming out of each side between the two columns
and double clicking.