Each line in ~/.config/lxsession/LXDE/autostart represents a command to be executed. If a line starts with @, and the command following it crashes, the command is automatically re-executed. For example:
~/.config/lxsession/LXDE/autostart
@lxterminal
@leafpad
Note:
These commands do not end with a & symbol.
There is also a global autostart file at /etc/xdg/lxsession/LXDE/autostart. If both files are present, LXsession only executes the local file as of v0.4.9