i 'm sorry to say that this should seal the deal - arnold is not , nor will he be , back . 
(ROOT (S (NP (PRP i)) (VP (VBP 'm) (ADJP (JJ sorry) (S (VP (TO to) (VP (VB say) (SBAR (IN that) (S (S (S (NP (DT this)) (VP (MD should) (VP (VB seal) (NP (DT the) (NN deal) (, -) (NNP arnold))))) (VP (VBZ is) (RB not))) (, ,) (CC nor) (SINV (MD will) (NP (PRP he)) (VP (VB be))) (, ,) (ADVP (RB back))))))))) (. .)))
(ROOT (S (NP (PRP )) (VP (VBP ) (ADJP (JJ ) (S (VP (TO ) (VP (VB ) (SBAR (IN ) (S (S (S (NP (DT )) (VP (MD ) (VP (VB ) (NP (DT ) (NN ) (, ) (NNP ))))) (VP (VBZ ) (RB ))) (, ) (CC ) (SINV (MD ) (NP (PRP )) (VP (VB ))) (, ) (ADVP (RB ))))))))) (. )))