The Witchsmeller Pursuivant - S1-E5
Witchsmeller: The suspect has his head placed upon a block, and an axe aimed at his neck. If the man is guilty, the axe will bounce off his neck so we burn him. If the man is not guilty, the axe will simply slice his head off.
Answer: The closest we ever get to knowing his first name is in series 3, when he claims it's "Sod Off". Blackadder asks him in series 3 where this came from, and he replies "Well, when I was a kid, living in the gutter, I'd go up to the other kids and say 'Hello, I'm Baldrick'. And they'd say, 'Yes, we know. Sod off, Baldrick.'" The S in this series is likely a reference to that, but it's not addressed, and given this Baldrick is clearly different from the series 3 Baldrick, we can't draw a direct link.
Shay