Write a Dart program that takes in a file path and a character as inputs, reads the file, and prints out only the lines that begin with the given character, in lowercase. The program should ignore any lines that do not begin with the given character, and should strip any whitespace at the beginning and end of each line before checking the first character. The program should also be able to handle file paths that contain spaces or other special characters.
This prompt doesn't seem malicious.