Lock screen when I close the laptop lid

I’m quite sure that Ubuntu 7.0.4 (Feisty Fawn) with GNOME 2.18 locked my screen when I closed the lid of my laptop. Ubuntu 7.10 (Gutsy Gibbon) with GNOME with 2.20 did not until I made this change under the hood. The XML below can be imported with gconftool --load.

<gconfentryfile>
  <entrylist base="/apps/gnome-power-manager/lock">
    <entry>
      <key>blank_screen</key>
      <schema_key>/schemas/apps/gnome-power-manager/lock/blank_screen</schema_key>
      <value>
        <bool>true</bool>
      </value>
    </entry>
  </entrylist>
</gconfentryfile>