The 24-year-old, who has 32 international matches, helped United in fourth place in her first season in the English Women’s Super League.
By the time the season was interrupted by Covid-19’s pandemic, he had scored nine goals in 34 games over two years.
“It’s such an exciting time to be from the club,” Arnot told the Rangers website.
The 2020–21 season is scheduled to begin on Sunday, October 18, after the last period has been declared null and void.