In Gnome or Unity, you can delay the startup of an application by placing the following file in the following directory:
~/.config/autostart/firefox1.desktop
[Desktop Entry]
Type=Application
Name=Firefox
GenericName=Firefox
Comment=Sync Firefox
Exec=firefox ~/Desktop/map.html start -i
Icon=firefox
Hidden=false
NoDisplay=false
X-GNOME-Autostart-enabled=true
X-GNOME-Autostart-Delay=10
However, the x-gnome-autostart command does not work in xfce in Xubuntu. Is there a way to accomplish this in xfce?