Theodor Lehmann was a Norwegian musician whose dates are 1847-1915. I was able to find nothing else about him with a cursory search. His Ländliche Suite for violin and piano, op. 7, was published by Hansen in Copenhagen. Link to the score page on IMSLP: link.
The second movement (of three) is titled "Bauerntanz" and shows some hints of the Hardanger fiddle style. The design is curious -- on the surface a ternary form of the common sort, with A closing in the dominant key, B unstable but moving about and toward the dominant, and a prominent and full reprise in the main key. But B turns out to be nothing but unstable -- it's a longish (re)transition with no tune of its own -- and "the full reprise" turns out to be an entirely new tune, or C.
Here is the first half of A, a sentence with an expanded continuation phrase. The second half (not shown) repeats the theme but reaches a PAC on the dominant for the first ending; it veers off in striking way to the minor subdominant for the second ending.
The B-section takes its time reaching the dominant and then revs up to a scalar rush to the tonic, which opens the reprise.
The "false reprise" or C is a double period (Caplin's 16-measure period), in which the 8-bar antecedent is a sentence:
Here is the consequent of the double period, with the structural cadence (I have reproduced the coda underneath). It might take a little work to specify the individual tones, but overall the inverted arch is clear enough: ^8-^7-^6-^5-^5-^6-^7-^8.
Coda with a pedal tonic and a couple quick V-I repetitions. Notice that its principal gestures all run downward, a foil to the strong rush-upward in the cadences of the preceding theme.