Hi Wouto,
thank you for the tip with the ping `route get default | awk '(/gateway/){print $2}'`
Unfortunately, this does not help.
I get several request timeouts regularly, sometimes for longer times.
So it is more or less a diagnostic tool, not a remedy.
But the diagnose is:
WLAN access is lost - my local LAN printer disappears / reappears.
So, internet access is only one symptom of general WLAN illness in Lion.
WIFI connection can drop every five minutes if Lion feels like it.
Really nice.
The only "remedy" is to close WIFI and then reconnect.
I even installed a second WIFI router to switch between the two to make this task faster.
And this is very tedious.
Funnily enough, Apple Care advised me to boot into recovery partition and reinstall.
But this fails, as internet access is needed ⚠
All the best
Martin