So, in the LW Agenda, after the address and opening litany for Ash Wednesday, the rubrics direct you to continue with the OT reading - in other words, the address and litany replace the entrance rite entirely.
I'd posted all the above over on ALPB and Pr. Zimmerman wrote me to inform me of his practice which makes the absolute most sense of out of the confusing rubrics. Here's his practice:
Lenten Address (from LSB Altar Book)
Salutation and Collect of the Day
Hymn of Day
Service of Ashes: The Litany, Blessing of Ashes, Imposition of Ashes, Declaration of Grace
and then Service of the Sacrament as usual.
I like his immensely because it is clear, it simplifies the service, it gives you the opportunity to preach upon the practice before inviting folks up for the ashes, and it avoids the needless repetitions (Western liturgy does NOT like repetition in general!) of the Litany at the beginning and then the Prayer of the Church following the sermon. It totally preserves the rubrics concern that some form of declaration of grace be spoken after the ashes are distributed. I think it's the best solution I've yet seen to the rather confusing rubrics in Lutheran Service Book on this matter.
One more matter of note - I also appreciate Pr. Mozolak's practice of reminding those who receive the ashes, not only that they are dust and to dust they shall return, but that they are Christ's and to Christ they shall return. I'm not sure what to do with that yet, but I like it. A lot.