Switch the operating system ;-)
*nix init scripts allow execution of arbitrary commands after the wlan comes up. Same goes for normal (wired) ethernet connections.
The waiting script mentioned above is only a crude hack. Even if you make the application wait before launching you never know WHEN the wlan is really up. Maybe the net is currently down, the waiting script won't detect this.
Something that could solve your problem correctly would be this application:
File monitor, event log watcher, alerter.
It's a bit of an overkill but it should do what you want (trigger application startup when the wlan connection is established).
Jam it back in, in the dark.