How can I correct the alignment of an acronym expansion in a table?

I’m using the package acronym to handle acronyms in my
document. Unfortunately, when expanding them inside a table
they become shifted downwards. Here’s a minimal example:

documentclass{article}
usepackage[nolist]{acronym}
begin{document}

begin{acronym}
  acro{LONG1}{My extra super long acronym}
  acro{LONG2}{Yet another very long acronym}
end{acronym}

begin{tabular}{ | p{3cm} | p{3cm} |}
  hline
  ac{LONG1} & Line 1  hline
  ac{LONG2} & Line 2  hline
end{tabular}

end{document}

Ideally, I’d like them to be aligned to the top and not
justified. How can I achieve that?