> This doesn't solve the problem directly but putting spaces around the 1
> works:
>
> --8<---------------cut here---------------start------------->8---
> #+BEGIN_LaTeX
> \newcommand{\norm}[ 1 ]{\lVert#1\rVert}
> #+END_LaTeX
> --8<---------------cut here---------------end--------------->8---
>
> (and also works with the header version).
>

Yes, it's not a big deal, but the header version doesn't have this problem
anymore.

Ruud