Sure.

select '-' || replace(WSTEXT,chr(10),chr(10)||'-')
from table1;

If there is any chance that there coluld be CHR(10) as the first character in the first line, you should use the following to prevent two consecutive '-' characters to appear in the first line:

select '-' || replace(ltrim(WSTEXT,CHR(10)),chr(10),chr(10)||'-')
from table1;