Hi Ken -
Lots of great visuals ... lots of great lines. Lots of LINES.
I am feeling you have more than one song working here...

The lyric opens with the light and lovely firefly play ... I felt that once you got through the 1st chorus you were on to a new lyric. It didn't feel like the same song ..
The whole firefly analogy is gone... it's important because your intro made the firefly the core of the lyric

Yeah, I know a heart can burn, at times chill in sorrow
But since our spirits touched, I can only see tommorow
For in the place she holds me, the light gathers strong
And in her eyes of autumn lies the risin of the sun

The sea of life has tossed us on it flaying current
Set us down within a garden and let the calm set in
Without the beacon of her everlasting love
This vessel would be lost within a numbing fog
Cause.....

Just my thoughts Ken
You are a lovely writer...
Joanne