Orton finds the right folks to savor her brand of folk

“A line has been drawn! ... Are you with me -- or are you against me?” Beth Orton stood center stage behind the shield of her acoustic guitar. Bathed in a halo of gold light and pointing a finger Monday at the Avalon’s sparse crowd, she asked again: “So are you with me?”

Her head snapped back with laughter as the house whooped support, and the 6-foot British folk chanteuse giddily resumed the final show of her monthlong U.S. tour.

She posed an apt question, really: One is either pro-chick folk or con. In the wrong ears, Orton’s confessional lyrics, nimble unplugged strumming and Lilith Fair alumna status can be a little too squishy for comfort.

But the mixed-gender crowd was indeed pro-Orton, and after she and her four-piece band opened with “Heartland Truckstop” and a string of other tracks off her new “Comfort of Strangers” album, she warmed the audience to a rolling simmer revisiting vintage favorites.

Dismissing the band for a brief recess, she urged her former backing guitarist, Ted Barnes, who’d preceded her with his trio Clayhill, to join her onstage. The two intimately dueled on acoustics for oldies “Central Reservation” and “Paris Train,” gathering a momentum that drove the remainder of the set as she summoned back the band.

At this point, Orton hit her stride, her signature dry baritone, which was crackling and sputtering at the start, eased into smoother crooning, and her demeanor melted from artistic reticence to goofball jocularity.

She wrapped up the lengthy 18-song set with two encores, and anyone not previously rallied to her side was likely marshaled there by this final, powerful display of naked emoting.