[Jordeh]

That conditional would be:

<if condition="$post['invisible']==0"> ... </if>

This will only show it if the user is not invisible

So this:

<if condition="$post['lastactivity']"><div>$vbphrase[last_seen_online]: $post[lso_date] ($post[lso_time])</div></if>

would become this:

<if condition="$post['invisible']==0"><if condition="$post['lastactivity']"><div>$vbphrase[last_seen_online]: $post[lso_date] ($post[lso_time])</div></if></if>