Thanks so much, PFM--that did the trick. I did have to change one thing, though, which I thought I should mention here. For some reason, when I posted exactly what you posted, the <td> and </td> preceding and following the isset function did not render at all. I put the <td> in the echo line before and the </td> in the echo line after and it worked like a charm. Here's the snippet:
echo'<td width=\"150\">'.$row[ws_name].'</td><td>';
echo isset($lookup[$row['ws_status']]) ? $lookup[$row['ws_status']] : '';
echo'</td><td>'.$row[ws_id].'</td>';
Just out of curiosity, any idea why this happened? In any case, thanks again for the solution, and all for chiming in and sparing me a good deal of frustration.