Hi Nicolas

I would like to ask you to review the attached patch so I can change
it when necessary before I git push it.

> it probably means that `org-link-escape' is a bit too zealous (BTW
> why don't this function rely on `url-encode-url'?)

url-encode-url is a very good hint to solve a different issue that
I try to deal with:

(from http://lists.gnu.org/archive/html/emacs-orgmode/2013-10/msg00204.html)
On Sat, Oct 5, 2013 at 3:04 PM, Michael Brand
<michael.ch.brand@gmail.com> wrote:
> [...] related change that I will suggest with an ERT in a later
> patch: Just add "+" to org-link-escape-chars-browser.

"+" has not been added to org-link-escape-chars-browser yet and in the
meantime I realized that it should not be added in order to not break
existing Org links like:

    [[http://lists.gnu.org/archive/cgi-bin/namazu.cgi?idxname=emacs-orgmode&query="Release+8.2"]]

that work the same as

    [[http://lists.gnu.org/archive/cgi-bin/namazu.cgi?idxname=emacs-orgmode&query="Release
8.2"]]

Better is to change the function org-link-escape-browser to use
url-encode-url when available (since Emacs 24.3). With this I can
write my use case to open a browser with +subject:"Release 8.2" in the
query field now as an Org link written manually with %2B for the "+"
at the beginning and %25 for its "%" like this

    [[http://lists.gnu.org/archive/cgi-bin/namazu.cgi?idxname=emacs-orgmode&query=%252Bsubject:"Release+8.2"]]

or

    [[http://lists.gnu.org/archive/cgi-bin/namazu.cgi?idxname=emacs-orgmode&query=%252Bsubject:"Release
8.2"]]

Link escaping in org-store-link and link unescaping in the first part
of org-open-at-point are not changed, this is important to keep
backward compatibility with old Org links. I have used this patch for
several weeks on Emacs 24.3.2 without any problem.

Michael