Meaning of the word "FOR" used at the beginning of a sentence

No, it can mean several things, and I'd say your example is an odd usage. It's either a poem or it's fairly old usage (or both).

Ways I'd expect to see a modern sentence start with "for" would be:

• For some time, he had been wondering if this was the right thing to do.

• For example, red cars tend to get more speeding tickets than blue cars.

• For many of us, a challenging job is more important than a high-paying job.

• For which crime are you arresting me?

"For" may mean "since", "because". For example, take this song from Nick Cave:

They call me The Wild Rose / But my name was Elisa Day / Why they call me it I do not know / FOR my name was Elisa Day (Where The Wild Roses Grow)

This use for "for" is pretty common, actually.

here in preceding sentence, "for" is being used as conjunction that means because. Generally, you can't use "for" as a conjunction at the beginning of a sentence. Most of time, "for" is used for giving reason. ex- I am here, for she is ill.

You can edit your sentence adding 'comma' in place of 'period' just before for.