How to find matches between multiple conditions?

Question

Regular Expressions

You need to find breaks if:
1. the line ends with a small letter + line break + the next line also starts with a small letter.
2. the line ends with a small letter + comma + line break + the next line also starts with a small letter.
This is necessary in order to later replace it with a space.

So far I've used it (?<=[a-z]\n)(.*)(?=^[a-z])for:
Or (?<=[a-z]\,\n)(.*)(?=^[a-z])

Two regular expressions work separately, but I can't mold them together...

Test text
the Olympic athletes of swimming pool,
It's not good like the women can do it,
always get flamed
It all goes back to my job
to that awful story Heaven
And the root of it equal thirty three

But it still doesn't work correctly. For example, after running a regular expression, you should get:

Test text the Olympic athletes of swimming pool,
It's not good like the women can do it, always get flamed
It all goes back to my job to that awful story Heaven
And the root of it equal thirty three.

Answer 1

find /([az]),?\n([az])/g
replace \1 \2
or /(?<=[a-z]),?\n(?=[a-z])/greplace with space