A cleaner way is probably to set a proper variable from the .tcl side based on the connection locale and to test then with something along the following lines:
<if @have_localized_help.id@ not nil>
Help: #mysite.@elements.id@_help#
</if><else>
No help available.
</else>
or even define your help-widget via an own tag:
<my_help_widget id="@id@" />
