\documentclass[twoside,english]{elsarticle}
\usepackage[T1]{fontenc}
\pagestyle{headings}
\usepackage{amsthm}
\makeatletter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Textclass specific LaTeX commands.
\theoremstyle{plain}
\newtheorem{thm}{\protect\theoremname}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
% specify here the journal
\journal{Example: Nuclear Physics B}
% use this if you need line numbers
%\usepackage{lineno}
\makeatother
\usepackage{babel}
\providecommand{\theoremname}{Theorem}
\begin{document}
\begin{frontmatter}{}
\title{This is a specimen title\tnoteref{t1,t2}}
\tnotetext[t1]{This document is a collaborative effort.}
\tnotetext[t2]{The second title footnote which is a longer longer than the first
one and with an intention to fill in up more than one line while formatting.}
\author[rvt]{C.V.~Radhakrishnan\fnref{fn1}\corref{cor1}\corref{cor2}}
\ead{[email protected]}
\author[rvt,focal]{K.~Bazargan\fnref{fn2}}
\ead[url]{http://www.elsevier.com}
\fntext[fn1]{This is the specimen author footnote.}
\fntext[fn2]{Another author footnote, but a little more longer.}
\cortext[cor1]{Corresponding author}
\cortext[cor2]{Principal corresponding author}
\address[rvt]{River Valley Technologies, SJP Building, Cotton Hills, Trivandrum,
Kerala, India 695014}
\address[focal]{River Valley Technologies, 9, Browns Court, Kennford, Exeter, United
Kingdom}
\begin{abstract}
Abstract, should normally be not longer than 200 words.
\end{abstract}
\begin{keyword}
quadruple exiton \sep polariton \sep WGM \PACS 71.35.-y \sep 71.35.Lk
\sep 71.36.+c \MSC[2008]23-557
\end{keyword}
\end{frontmatter}{}
\section{Introduction}
Bla bla,
\end{document}