[09:46] * Now talking in #chan
HERE JOIN event
[09:46] * Topic is 'test'
[09:46] * Set by RoCk on Sun Jun 17 09:44:55
HERE raw 353
HERE raw 366

Using the join event is the obvious choice. Not to mention that the info message to be replaced is triggered by the join event, not any numeric raw message.

on *:JOIN:#: {
if ($nick == $me) echo -a HERE raw JOIN
}
raw 353:*: {
echo -a HERE raw 353
}
raw 366:*: {
echo -a HERE raw 366
}