Utterly - where are you getting this nonsense that you can't start a sentence with and, yet, for, so ?
For we do not have a high priest who is unable to empathize with our weaknesses, but we have one who has been tempted in every way, just as we are—yet he did not sin. The Bible
And yet I have had the weakness, and have still the weakness, to wish you to know with what a sudden mastery you kindled me, heap of ashes that I am, into fire. Dickens (that's "and" and "yet"!)
So now the Admiralty wireless whispers through the ether to the tall masts of ships, and captains pace their decks absorbed in thought. It is nothing. It is less than nothing. It is too foolish, too fantastic to be thought of in the twentieth century. Or is it fire and murder leaping out of the darkness at our throats, torpedoes ripping the bellies of half-awakened ships, a sunrise on a vanished naval supremacy, and an island well-guarded hitherto, at last defenceless?
Churchill ("So" and "Or"!)