In [14]: L = [['lorem', ['a', 'b', 'c', 'd']], ['ipsum', ['e']], ['dolor', ['f', 'g']], ['sit', ['h', 'i']]]
In [15]: '; '.join("%s (%s)" %(elem[0], " + ".join(elem[1])) for elem in L)
Out[15]: 'lorem (a + b + c + d); ipsum (e); dolor (f + g); sit (h + i)'
また
In [18]: L = [(e[0], " + ".join(e[1])) for e in L]
In [19]: L
Out[19]:
[('lorem', 'a + b + c + d'),
('ipsum', 'e'),
('dolor', 'f + g'),
('sit', 'h + i')]
In [20]: '; '.join("%s (%s)" %(e[0], e[1]) for e in L)
Out[20]: 'lorem (a + b + c + d); ipsum (e); dolor (f + g); sit (h + i)'