If I'm not mistaken LXDE uses openbox, and so your "autostart" script should be in "/home/usernamerhere/.config/openbox/autostart.sh".
And BTW if you don't know, you do have to put a "&" at the end of each process or it will wait until that process ends to start the next...
For example my autostart.sh is:
feh --bg-scale /home/scrivener/Pictures/a64background.png &
xcompmgr -cfF -t-9 -l-11 -r9 -o.95 -D6 &
guake --sync /etc/x11/Germinal &
Which starts conky, tint2, gnome-settings-daemon, and volume icon under default settings, and xcompmgr, guake, and feh under my custom options...
Hope it helps, but if LXDE doesn't use openbox then I just wasted my time NOT helping you...