Crosby was born in Walker, Newcastle upon Tyne in 1960. Her father died in a car accident when she was two years old, leaving her mother to raise Lorraine and her two sisters and brother. She attended Walker Comprehensive, and she sang in school and church choirs and played the violin in the orchestra but didn't start singing until she was 20.

Inspired by an early 1980s television performance by Lene Lovitch, Crosby searched the noticeboard for bands wanting singers at the guitar shop Rock City in Newcastle (now Air Guitars). After joining several bands she set up a five-piece cabaret band, 'Foxy', who toured playing to British and American servicemen throughout the early eighties.

Back in Newcastle, she met Stuart Emerson, who was looking for a backing singer for his band. They began writing together, and also became a couple. In the early 1990s, Crosby sent songwriter and producer Jim Steinman some demos of songs she had written with Emerson. Steinman asked to meet them, and the couple decided that they would move to New York to give their careers a boost. They then followed Steinman after he moved to Los Angeles, living in the Magic Hotel, where all of Meat Loaf's band were staying, until they could find somewhere permanent to live. Steinman, who became their manager, secured them a contract with Meat Loaf's recording label MCA. While visiting the label's recording studios on Sunset Boulevard, Crosby was asked to provide guide vocals for Meat Loaf, who was recording the song "I'd Do Anything for Love (But I Won't Do That)". Cher, Melissa Etheridge and Bonnie Tyler had been considered for the role. The song was a commercial success, becoming number one in 28 countries. However, as Crosby had recorded her part as guide vocals, she did not receive any royalties from the song. Also, Crosby did not appear in the Michael Bay-directed music video, where model Dana Patrick mimed her vocals. Meat Loaf promoted the single with American vocalist Patti Russo performing the live female vocals of this song at his promotional appearances and concerts.

Crosby regularly performed at holiday camps and social clubs in England until April 2005 when she took a break from live work. In 2005 she sang a duet with Bonnie Tyler for the track "I'll Stand by You" from the album Wings.

In 2005 Crosby appeared as a contestant on ITV's The X Factor. She performed "You've Got a Friend" and progressed to the second round after impressing judges Louis Walsh and Sharon Osbourne but Simon Cowell expressed doubt saying she "lacked star quality." Crosby failed to progress beyond the second round, despite telling the judges the competition was "her last shot".

She returned to live performance in April 2007.

In November 2007 Crosby appeared on the BBC Three TV show "Most Annoying Pop Songs We Hate To Love" discussing the Meat Loaf track "I'd Do Anything for Love (But I Won't Do That)" which featured at no. 76.

In November 2008 she appeared at Newcastle City Hall with special guest Bonnie Tyler to launch her self-produced album entitled Mrs Loud. In April 2009 she was also featured on The Justin Lee Collins Show and performed a duet with Justin singing "Dead Ringer for Love"

She performs in a soul/Motown covers band with her partner, the musician Stuart Emerson.