This week the Dallas Symphony Orchestra had to find a substitute when Dutch conductor Jaap van Zweden’s visa wasn’t issued in time for his scheduled performances. “Visa process that once took 45 to 60 days has more than doubled, with 4 1/2 months being the average time at present. Since applications for work visas are not accepted more than six months before the date of entry, there’s little room to deal with the problem of visas that take longer than average.”