Can somebody explain this event in Sql Server Profiler?

Sql Server 2005; debugging a web application that accesses multiple databases.

I'm debugging some tsql in my web application using Profiler. Every once in awhile an Audit Login event will show up. This event contains the following text data:

-- network protocol: TCP/IP
set quoted_identifier on
set arithabort off
set numeric_roundabort off
set ansi_warnings on
set ansi_padding on
set ansi_nulls on
set concat_null_yields_null on
set cursor_close_on_commit off
set implicit_transactions off
set language us_english
set dateformat mdy
set datefirst 7
set transaction isolation level read committed

When this event shows up, there is a noticable lag in the time it takes for the query to return. I'm wondering if anybody can tell me

1) What causes this event

2) How often can I expect this to happen. I.e., it happens once per application instance, once per application instance touching a database for the first time, once every X minutes, once every x queries executed, etc.

TIA!

Every time a new connection is made by a client -and is very normal and necessary.